The coatings industry (paints, adhesives, paper, leather and textile coatings) employs latexes as binders in film-forming formulations which in some cases require post-crosslinking, this being intended to improve the properties of the coatings obtained, especially in terms of their solvent content and their mechanical properties, and to reduce the surface tack, thereby allowing a reduction in the soiling potential in the case of exterior paints.
This step of post-crosslinking must be adapted to the area of application and to the operating conditions (in the field of paints no heat treatment of the coating can be envisaged, whereas the textile industry currently employs processes of thermal crosslinking at temperatures of the order of 160.degree. C.).
Irrespective of the intended application, the objective is to obtain a system which is as reactive as possible at the lowest possible temperature whilst being a one-component system; in other words, one which is ready to use and is stable on storage, these two requirements very often being contradictory.
Moreover, owing to the constraints in terms of the protection of people and the environment, another objective consists in reducing the emission of volatile organic compounds, like the solvents used for the temporary plastification of the latexes (reduction in the film-forming temperature without diminishing the glass transition temperature of the copolymer and hence without lessening the mechanical properties of the film), formaldehyde, etc.